Known from document EP 0 413 985 [U.S. Pat. No. 5,123,606] is a reel mandrel for straight-edged winding of or unwinding of metal strip to form a coil or from a coil, in particular for winding rolled hot strip, comprising a driven reel mandrel which is supported so as to be rotatable, substantially consisting of a mandrel body, segments and spreading bar, wherein the segments can be spread in the radial direction with the intermediary of the spreading bar which is movable axially in the mandrel body and a coupling of a drive rotating with the reel mandrel, which is movable with the spreading bar. In this case, the coupling is arranged with a play corresponding to the spreading of the reel mandrel between an emergency de-spreading device and the housing of the hydraulic drive, wherein the emergency de-spreading device and the housing of the hydraulic drive are immovable with respect to the mandrel body in the axial direction and wherein the movement of the coupling in the sense of a reduction in the diameter of the reel mandrel is limited by the emergency de-spreading device and the emergency de-spreading device makes it possible to additionally release the axial mobility of the spreading bar connected to the coupling by a certain amount of distance. Such a reel mandrel satisfactorily fulfils its allotted task of winding hot strip.
DE 103 47 262 B3 discloses a grease distribution system for a reel mandrel whereby the grease distributors are arranged in a grease distribution ring which is flange-mounted to the mandrel shaft at its end face and which is provided with channels which are connected to axial bores arranged in the mandrel shaft, the bores leading directly and/or via cross-bores to the lubrication points. The reel to be designated as a standard reel mandrel in this document further consists of a mandrel body, a spreading bar with links for holding the segments. A shaft is screwed onto the end face of the mandrel body to which a roller bearing with housing is attached. This unit is then supported by a pivotal holder. The pivotal holder (hereinafter called mandrel mounting) grips around the roller bearing with its housing from two sides and supports this during the winding process. During removal of the coil the mandrel mounting pivots away from the roller bearing and its housing and thus exposes the path for removal of the coil.
The mandrel body is configured as open at the front so that the spreading bar with the links and the pressure plates to the segments can be mounted inside the mandrel body.
This design allows the spreading bar, the links and the pressure plates to be mounted easily. The rigidity of this design is sufficient for the usual loading.
As a result of the increasing tendency to roll and wind increasingly higher-strength steels, the requirement for the reel mandrel of a hot-strip train will increase substantially. The loading can easily be between twice and three times the loading compared with a standard reel mandrel.
An example of these high-strength steels are the tube quality stages according to the American API standard grade B and the quality stages X42 to X80. At present, the tube quality stages X100 to X120 are being developed and beginning to be used. These materials constitute a completely new development. They should satisfy the requirement for higher strength, improved corrosion resistance and an increase in the collapse resistance (for marine use).